Independently rotated pneumatic rock drill

ABSTRACT

An independently rotated, muffled pneumatic rock drill comprising an impact mechanism housing in which an impact mechanism and a rotation motor are located and in which housing also is enclosed an air volume into which the exhaust air from both the impact mechanism and the rotation motor is discharged. The housing comprises at least two separable parts, one of which is a detachable cover surrounding the rotation motor.

0 United States Patent 1151 3,684,033 Ahlberg et al. [451 Aug. 15, 1972INDEPENDENTLY ROTATED [56] References Cited PNEUMATIC ROCK DRILL UNITEDSTATES PATENTS Inventors: Erik Johan Victor g; 695w 1,642,949 9/1927Gilman ......173/105 Ballard Ekwall, f Nacka; 2,778,605 1/1957 Hunn..173/105 Ronald Lmdqum, 3,385,378 5/1968 Weber et al. ..173/105 Sweden3,332,502 7/1967 Vinnik ..173/105 [73] Assignee: Atlas Copco Aktiebolag,Nacka,

S d Primary Examiner-James A. Leppink Filed: J 1971 Att0rney-Bauer andGoodman [2]] Appl. No.: 156,775 [57] ABSTRACT Relaed s Application DataAn independently rotated, muffled pneumatic rock drill comprising animpact mechanism housing in [63] commuauoii'm'pan of Sen 77,233 which animpact mechanism and a rotation motor are 1970- Y located and in whichhousing also is enclosed an air volume into which the exhaust air fromboth the im- [52] US. Cl ..fi.21573/l05 pact mechanism and the rotationmotor is discharged Int. Cl. The i g comprisesrat least two Separablc pField of Search", ..l73/lO5-l09, 171

one of which is a detachable cover surrounding the rotation motor.

5 Claims, 4 Drawing Figures PATENTEDAus 15 m2 sum 2 or 5 1 Ems wwnr/////////////////////// /V/ INDEPENDENTLY ROTATED PNEUMATIC ROCK DRILLThis application is a continuation-in-part application of our co-pendingapplication Ser. No. 77,233 filed Oct. 1,1970.

This invention relates to an independently rotated pneumatic rock drill.The main object of the invention is to provide a muffled rock drill ofthe above mentioned type in which both the impact mechanism and therotation motor are effectively muffled.

Other objects of the invention will be apparent from the followingdetailed description and drawings wherein: 7

FIG. 1 is avertical elevational view, partly in section, of a rock drillembodying the invention.

., FIG. 2 is an enlarged cross sectional view taken along line IIII inFIG. 1.

FIG. 3 is a partly broken vertical elevational view of another rockdrill according to the invention and FIG. 4 is a cross sectional viewalong line IV-IV in FIG. 3.

Referring to FIGS. 1 and 2, 1 designates an impact mechanism housingwhich contains an impact mechanism 2. The impact mechanism comprises ahammer piston 3 which is slidable in a cylinder liner 4 that surroundsthe rear end of the hammer piston 3 and which is mounted in the housing.

v The cylinder liner 4 is provided with air exhaust means whichpreferably consists of rows of small diameter holes 5. This arrangementhas a primary silencing effect in that the hammer piston, during its themounting surface 9 for directing exhausted air towards the feedmechanism (not shown). This arrangement is advantageous in that the rockdrill guides and feed mechanism are blown clean and lubricated by theexhausted air.

In FIGS. 3 and 4 there is shown a rock drill according to anotherembodiment of the invention. This rock drill comprises an impactmechanism 21 and an independently working rotation motor 22 both beinglocated within a housing 23.

The impact mechanism 21 comprises a hammer piston 24 and a cylinderliner 25 the latter of which surrounds the rear part of the hammerpiston and is attached to the housing. As in the previously describedrock drill, the cylinder liner is provided with an exhaust means in theform of rows of small diameter holes 26 for accomplishing a primarysilencing of the impact mechanism.

The rotation motor 22 rotates the drill rod 27 through a speed reductiongear 28 and a chuck bushing (not shown in detail). The rotation motor 22is provided with an exhaust pipe 29, the length of which may forwardmovement towards the neck of the drill steel l1, successively uncoversone row after the other. The pressure within the cylinder is therebysuccessively lowered. Thus, violent exhaust air pressure shocks from theimpact mechanism are avoided.

The impact mechanism housing 1 is large enough to also surround aseparate rotation motor 6. The rotation motor 6 rotates the drill steel11 independently of the impact mechanism through a speed reduction gearand a chuck bushing (not shown in detail). The rotation motor may be avane type motor provided with an exhaust pipe 7 at its rear end. Theexhaust pipe 7 preferably has a length that is tuned to the wavelengthof the exhaust sound in order to avoid resonances and to effect aprimary silencing of the rotation motor.

Within the impact mechanism housing 1 there is enclosed an air volume 8which surrounds the rotation motor 6 as well as the cylinder liner 4(see FIG. 2). The air exhaust from both the impact mechanism and therotation motor are discharged into this air volume 8, whereby asecondary silencing is effected in that the remaining air pressureshocks are effectively absorbed by the air volume.

Furthermore, the impact mechanism housing 1 is provided with a mountingsurface 9 for mounting the rock drill on a slide (not shown). Themounting surface is so located on the housing 1 that the rock drill ismountable on the slide with the rotation motor close to the slide. Bylocating the impact mechanism outside the rotation motor a very shortdistance is obtained between the outermost surface of the rock drill andthe drill steel, which makes it possible to drill holesclose up to awall or a roof.

Moreover, the impact mechanism housing 1 is provided with air outletopenings 10 which extend through be tuned relative to the exhaust soundin order to avoid resonances and to effect a primary silencing of therotation motor.

The housing 23 according to this embodiment of the invention is dividedinto two parts, one of which constitutes a detachable cover 230,surrounding just the rotation motor 22. As the housing consists of twoseparable parts the accessability especially of the rotation motor, isincreased.

For establishing a secondary silencing there is enclosed an air volume30 in the housing 23, into which air volume the exhaust air from theimpact mechanism 21 as well as the rotation motor 22 is discharged. Thistwo-piece type of housing makes it possible to more easily and betterdesign the housing to obtain a more efficient silencing than in thepreviously described embodiment. The housing 23 is also provided with anexhaust pipe 31 through which the exhaust air from both the impactmechanism and the rotation motor is discharged. The exhaust pipe 31,which is preferably tuned, as is pipe 29, further enhances silencing.

Moreover, the housing 23 is provided with means 32 for mounting the rockdrill on a slide (not shown). It is also provided with a nut 33 forcooperation with the feed screw of a feed device.

What we claim is:

I. An independently rotated pneumatic rock drill comprising an impactmechanism housing, an impact mechanism hammer piston slidably mounted insaid housing, a cylinder liner surrounding the rear end of said hammerpiston and provided with air exhaust means, a separate rotation motorlocated within said housing and means defining an air volume enclosedwithin said housing and surrounding the cylinderliner as well as therotation motor, into which air volume, the I exhaust air from the impactmechanism and the rotation motor is discharged, said impact mechanismhousing comprising at least two separable parts, one of which is adetachable cover surrounding the rotation motor.

2. The pneumatic rock drill of claim 1, wherein the rotation motor isprovided with an exhaust pipe the length of which is tuned relative tothe wavelength of wherein said detachable cover surrounds only therotation motor.

5. The pneumatic rock drill according to claim 1, wherein saiddetachable cover is provided with an exhaust pipe through which theexhaust air from both the impact mechanism and rotation motor isdischarged.

NTTED STATES PATENT QTTT Patent; NO. 3 ,684 Dated August 15 1972Inventofls) AHLRERG et a1 It is certified that error appears in theabove-identified patent and that; said Letters 'Pqtent arehereby-corrected as shown below:

Column 'l line {delete "co-pending line 5 insert after "1970" *--whichissued as'pajzent No. 3 659,657 on May 2, 197-2--. j T

Signed and sealed gthis 9 ch day of January 1973 (SEALl l I Attest:

' EDWARD M.,FLETCHER,JR. A1;tes cin1g Officer- ROBERT GOTTSCHALKCommissioner of Patents FORM PC4050 (70459)

1. An independently rotated pneumatic rock drill comprising an impactmechanism housing, an impact mechanism hammer piston slidably mounted insaid housing, a cylinder liner surrounding the rear end of said hammerpiston and provided with air exhaust means, a separate rotation motorlocated within said housing and means defining an air volume enclosedwithin said housing and surrounding the cylinder liner as well as therotation motor, into which air volume, the exhaust air from the impactmechanism and the rotation motor is discharged, said impact mechanismhousing comprising at least two separable parts, one of which is adetachable cover surrounding the rotation motor.
 2. The pneumatic rockdrill of claim 1, wherein the rotation motor is provided with an exhaustpipe the length of which is tuned relative to the wavelength of theexhaust sound in order to avoid resonances and to effect a primarysilencing of the rotation motor.
 3. The pneumatic rock drill of claim 5,wherein the air exhaust means of the cylinder liner is comprised ofcircumferential rows of small diameter holes, which effect a primarysilencing of the impact mechanism.
 4. The pneumatic rock drill accordingto claim 1, wherein said detachable cover surrounds only the rotationmotor.
 5. The pneumatic rock drill according to claim 1, wherein saiddetachable cover is provided with an exhaust pipe through which theexhaust air from both the impact mechanism and rotation motor isdischarged.